Request Failed in OIM 11g

IAM2050014 error found after any request was raised, this has occured after initiating the approval process. error occured:- IAM-2050014:An error occurred while initiat开发者_运维问答ing approvals for request oracle.iam.platform.workflowservice.exception.IAMWorkflowException: Tasklist mapping failed for workflowdefinition: default/RequesterManagerApproval!1.0 due to javax.naming.NameNotFoundException: Unable to resolve 'TaskQueryService'. Resolved '' [Root exception is javax.naming.NameNotFoundException: Unable to resolve 'TaskQueryService'. Resolved '']; remaining name 'TaskQueryService'. The corresponding error message is {1}.

please help !!!!